Abstract: Compositions for increasing the amount of available silica, calcium, magnesium, and sulfur are described herein. The compositions contain calcium silicate (CaSiO2) and magnesium sulfite (MgSO3). Calcium silicate may be in the form of calcium silicate slag. Magnesium sulfite may be a by-product obtained from power plants. In one embodiment, the composition is in granular form and contains 65-90% (wt) calcium silicate slag, 20-30% (wt) magnesium sulfite, 0-5% (wt) expandible clay, and 2-10% (wt) residual moisture (H2O). In a preferred embodiment, the granules contain 31% (wt) silica, 22% (wt) calcium, 3% (wt) magnesium, and 4% (wt) sulfur. In a second embodiment, the composition is non granular and contains 75-90% (wt) calcium silicate slag, 10-20% (wt) magnesium sulfite and 0-10% (wt) H2O. The compositions may be applied to golf courses or residential or commercial lawns to improve the growth of grasses and their resistance to disease and insects.